It's a genetics thing. I'm not sure if the eye color is a single gene(makes probabilities a lot easier, hehe) but two bi-eyed could have puppies with all combos, two blues will have blue eyed pups, one blue eyed and one bi-eyed will have blues and bis but no browns, or it could have to do with which cells migrate where in the developing embryo(like a zebra or tabby cat). I think two blue and bi colored are more common than two brown though. In terms of "normal" eyes, Huskies are one of only two or three breeds that wont be disqualified in dog shows for having bi/blue-eyes. Interestingly, a pure bred Malamute will never have blue eyes (one or two).